About Versions of the Unicode® Standard
This page describes:
For specific details regarding individual numbered versions of
the Unicode Standard, see the
Archive of Unicode Versions. For details regarding dates of past releases and publications, see
History
of Release and Publication Dates.
Version numbers for the Unicode Standard consist of three fields,
denoting the major version, the minor version, and the update
version, respectively. For example, “Unicode 3.1.1” indicates major
version 3 of the Unicode Standard, minor version 1 of Unicode 3, and
update version 1 of minor version Unicode 3.1.
The differences between major, minor, and update versions are as follows:
Major and Minor Versions
Major and minor versions have significant additions to the standard, including, but not limited to, additions to the repertoire of encoded characters. Both are published as updated text of the standard, together with associated updates to Unicode Standard Annexes and the Unicode Character Database. Such versions consolidate all errata and corrigenda and supersede any prior documentation for major, minor, or update versions.
A major version typically is of more importance to implementations; however, even update versions may be important to particular companies or other organizations. Major and minor versions are often synchronization points with related standards, such as with ISO/IEC
10646.
Prior to Version 5.2, minor versions of the standard were
published as online amendments expressed as textual changes to the
previous version, rather than as fully consolidated new editions of
the text.
Update Version
An update version represents relatively small changes to the
standard, typically updates to the data files of the Unicode
Character Database. An update version never involves any additions
to the character repertoire. These versions are published as
modifications to the data files, and, on occasion, include
documentation of small updates for selected errata or corrigenda.
Formally, each new version of the Unicode Standard supersedes all
earlier versions. However, because of the differences in the way
versions are documented, update versions generally do not obsolete
the documentation of the immediately prior version of the standard.
Starting with Unicode 3.0.1, update versions are published as
stable version pages online. Prior to that version, update versions
were simply documented with the list of relevant data file changes
to the Unicode Character Database. For historical reasons, update version numbers were not always consecutive prior to Unicode 3.0.
Schedule of Releases
Starting with Unicode 7.0, the Unicode Technical Committee has decided to follow a more predictable
release schedule. A new major version of the standard will be released each year. Starting with Unicode 14.0, each of those releases is targeted for the third quarter of each year. Thus Unicode 14.0 was released in September 2021, Unicode 15.0 was released in September 2022, and so on. Minor and update versions
will be avoided, unless necessary to address particular issues
on a timely basis.
Documents and
Version Numbering
The documents associated with the major, minor, and update versions are called the major reference, minor reference, and update reference, respectively. For example, consider Unicode Version
3.1.1. The major reference for that version is The Unicode Standard, Version 3.0 (ISBN 0-201-61633-5).
The minor reference is Unicode Standard
Annex #27, The Unicode Standard, Version 3.1. The update reference is
Unicode Version
3.1.1. The exact list of contributory files, UAXs and the
Unicode Character Database, can be found on the page
Components for Version 3.1.1.
The Unicode Consortium archives each version of the standard.
Each archived version consists of the set of versioned contributory data files.
For earlier versions of the
standard, these include the material from the major reference, unless
superseded by files in the update version. The Unicode Consortium
maintains online access to archival copies of all contributory files
available in electronic form. For the earliest versions, some material
was only published in paper form. The Consortium maintains private
archive records of these. In addition, they are available in many libraries.
Certain files change with every version of the Unicode Standard, and either have corresponding version numbers, such as UnicodeData-3.1.0.txt, or, for more recent versions, are located in versioned directories, such as
10.0.0/ucd/UnicodeData.txt. Other files have independent version
numbers, such as tr7-4.html for the fourth version of
Unicode Technical Report #7. The latest version of each file will
also be copied under the corresponding file name with no version,
such as UnicodeData.txt or tr7.html.
The latest versions of all of the Unicode Character Database
files are kept in
https://www.unicode.org/Public/UCD/latest/. These files have no
version number suffix, so that a link to a file in that
directory will always point to the latest version.
The component specifications linked from the
Archive of Unicode Versions contain precise lists of the contents of
each version of the standard. Each specification for version 3.0
or later also includes the recommended citation format for
that version, such as:
The file
DerivedAge.txt contains a list showing when various code points
were designated in Unicode. This can be useful in determining the
version in which a character first appears.
For versions 5.2 and later, a summary of the modifications in the Unicode Character Database can be found in
Unicode Standard Annex #44, Unicode Character Database. That annex also specifies which character properties in the UCD are normative, informative, or contributory. For earlier versions, such information is found instead in the documentation file, UCD.html.
The component specifications of the
Archive of Unicode Versions use the following table to indicate the
change status of data files between versions.
Key
N |
New in this release |
D |
Data change (possibly also format/text change) |
F |
Data format change (possibly also text change) |
T |
Text annotation change |
- |
Unchanged |
Zipped data files are also available. Those zip files are complete
for versions 4.1 and later. For versions earlier than 4.1, the zip files
only include files that were changed between versions.
From time to time it may be necessary to publish errata or
corrigenda to the Unicode Standard. Such errata and corrigenda will
be published on the Unicode Web site. To report errors in the
standard, please use the
contact form.
Errata. Errata correct errors in the text or other
informative material, such as the representative glyphs in the code
charts. See
Updates and Errata for the list of known
current errata for the standard. Whenever a new major version of the
standard is published, all corrections for errata up to that point are incorporated
into the text.
Corrigenda. Occasionally errors may be important
enough that a corrigendum is issued prior to the next version of the
Unicode Standard. Such a corrigendum does not change the contents of
the previous version. Instead, it provides a mechanism for an
implementation, protocol, or other standard to cite the previous
version of the Unicode Standard with the corrigendum applied. If a
citation does not specifically mention the corrigendum, the
corrigendum does not apply. See
Corrigenda for more information about
corrigenda to the standard.
Major versions of the Unicode Standard from Version 3.0 to Version 5.0 were published both as printed books and as electronic editions on this Web site. The electronic edition contains all of the chapters of the book (in pdf format). The content of both editions is intended to be identical, but in case of any inadvertent errors in production of the electronic edition, the printed edition should be taken as authoritative for those versions.
For most character encodings, the character repertoire is fixed (and often small). Once the
repertoire is decided upon, it is never changed. Addition of a new abstract character to a
given repertoire creates a new repertoire, which will be treated either as an update of the
existing character encoding or as a completely new character encoding.
For the Unicode Standard, by contrast, the repertoire is inherently open. Because Unicode
is a universal encoding, any abstract character that could ever be encoded is a potential candidate
to be encoded, regardless of whether the character is currently known.
Each new version of the Unicode Standard supersedes the previous one, but implementations—and, more significantly, data—are not updated instantly. In general, major and
minor version changes include new characters, which do not create particular problems
with old data. The Unicode Technical Committee will neither remove nor move characters.
Characters may be deprecated, but this does not remove them from the standard or from
existing data. The code point for a deprecated character will never be reassigned to a different
character, but the use of a deprecated character is strongly discouraged. Generally these
rules make the encoded characters of a new version backward-compatible with previous
versions.
Implementations should be prepared to be forward-compatible with respect to Unicode
versions. That is, they should accept text that may be expressed in future versions of this
standard, recognizing that new characters may be assigned in those versions. Thus they
should handle incoming unassigned code points as they do unsupported characters. (See
Section 5.3, Unknown and Missing Characters.)
A version change may also involve changes to the properties of existing characters. When
this situation occurs, modifications are made to the Unicode Character Database and a new
update version is issued for the standard. Changes to the data files may alter program
behavior that depends on them. However, such changes to properties and to data files are
never made lightly. They are made only after careful deliberation by the Unicode Technical
Committee has determined that there is an error, inconsistency, or other serious problem
in the property assignments.
Since Unicode is an open standard, it is important not to
over-specify the version number. Wherever the precise behavior of
all Unicode characters needs to be cited, the full three-field
version number should be used, as below in example (1).
- The Unicode Standard, Version 3.1.1
- The Unicode Standard, Version 3.1
- The Unicode Standard, Version 3.0 or later
- The Unicode Standard
Where the precise character repertoire is significant, but the
precise character properties are not at issue, then the third field
can be omitted, as in example (2). Where some basic level of
content is all that is important, phrasing such as in example (3)
can be used. Where the important information is simply the overall
architecture and semantics of the Unicode Standard, the version can
be omitted entirely, as in example (4).
Particular definitions or conformance clauses can also be cited,
such as:
Conformance clause C3 of The Unicode Standard,
Version 3.1
When citing the Unicode Character Database separately, use the
same format for version numbers.
The Unicode Character Database, Version 3.1.1
The versioning for Unicode Technical Reports and distinctions
among the different categories of report are explained on
Technical
Reports. The full form of a citation takes one of the following
forms:
- Unicode Standard Annex #9: The Bidirectional Algorithm,
Version 3.0.1
- Unicode Technical Standard #6: A Standard Compression Scheme
for Unicode, Version 3.1
- UTR #17: Character Encoding Model, Version 3.1
As above, the revision number can be omitted where not necessary.
Citations can be abbreviated using the formats below, although the
first citation should be spelled out for clarity. In particular, the
acronyms UCD, UAX, UTS, and UTR should be spelled out the first
time. The title of a UTR should be supplied with the first
reference.
- Unicode 3.1.1 (instead of The Unicode Standard, Version 3.1.1)
- Clause C3 of Unicode 3.1.1
- UCD 3.1.1
- UTS #10: Unicode Collation Algorithm
- UTS #10
When claiming conformance, the precise version should be used,
such as:
- "This product conforms to The Unicode Standard, Version
9.0.0".
- "This product conforms to UTS #10: Unicode Collation
Algorithm, Version 9.0.0".
The format for references to The Unicode Standard, Unicode
Standard Annexes, and other Unicode Technical Reports is illustrated
by the following examples. For the actual citations for references
to each version of the standard, see
the Archive of Unicode Versions.
Versioned
The Unicode Consortium. The Unicode Standard, Version 15.1.0, (South San Francisco, CA: The Unicode Consortium, 2023. ISBN 978-1-936213-33-7)
https://www.unicode.org/versions/Unicode15.1.0/
Versionless
The Unicode Consortium. The Unicode Standard.
https://www.unicode.org/versions/latest/
Version 15.0.0
The Unicode Consortium. The Unicode Standard, Version 15.0.0, (Mountain View, CA: The Unicode Consortium, 2022. ISBN 978-1-936213-32-0)
https://www.unicode.org/versions/Unicode15.0.0/
Version 14.0.0
The Unicode Consortium. The Unicode Standard, Version
14.0.0, (Mountain View, CA: The Unicode Consortium, 2021. ISBN 978-1-936213-29-0)
https://www.unicode.org/versions/Unicode14.0.0/
Version 13.0.0
The Unicode Consortium. The Unicode Standard, Version
13.0.0, (Mountain View, CA: The Unicode Consortium, 2020. ISBN 978-1-936213-26-9)
https://www.unicode.org/versions/Unicode13.0.0/
Version 12.1.0
The Unicode Consortium. The Unicode Standard, Version 12.1.0, (Mountain View, CA: The Unicode Consortium, 2019. ISBN 978-1-936213-25-2)
https://www.unicode.org/versions/Unicode12.1.0/
Version 12.0.0
The Unicode Consortium. The Unicode Standard, Version 12.0.0, (Mountain View, CA: The Unicode Consortium, 2019. ISBN 978-1-936213-22-1)
https://www.unicode.org/versions/Unicode12.0.0/
Version 11.0.0
The Unicode Consortium. The Unicode Standard, Version 11.0.0, (Mountain View, CA: The Unicode Consortium, 2018. ISBN 978-1-936213-19-1)
https://www.unicode.org/versions/Unicode11.0.0/
Version 10.0.0
The Unicode Consortium. The Unicode Standard, Version 10.0.0, (Mountain View, CA: The Unicode Consortium, 2017. ISBN 978-1-936213-16-0)
https://www.unicode.org/versions/Unicode10.0.0/
Version 9.0.0
The Unicode Consortium. The Unicode Standard, Version 9.0.0, (Mountain View, CA: The Unicode Consortium, 2016. ISBN 978-1-936213-13-9)
https://www.unicode.org/versions/Unicode9.0.0/
Version 8.0.0
The Unicode Consortium. The Unicode Standard, Version 8.0.0, (Mountain View, CA: The Unicode Consortium, 2015. ISBN 978-1-936213-10-8)
https://www.unicode.org/versions/Unicode8.0.0/
Version 7.0.0
The Unicode Consortium. The Unicode Standard, Version 7.0.0, (Mountain View, CA: The Unicode Consortium, 2014. ISBN 978-1-936213-09-2)
https://www.unicode.org/versions/Unicode7.0.0/
Version 6.3.0
The Unicode Consortium. The Unicode Standard, Version 6.3.0, (Mountain View, CA: The Unicode Consortium, 2013. ISBN 978-1-936213-08-5)
https://www.unicode.org/versions/Unicode6.3.0/
Version 6.2.0
The Unicode Consortium. The Unicode Standard, Version 6.2.0, (Mountain View, CA: The Unicode Consortium, 2012. ISBN 978-1-936213-07-8)
https://www.unicode.org/versions/Unicode6.2.0/
Version 6.1.0
The Unicode Consortium. The Unicode Standard, Version 6.1.0, (Mountain View, CA: The Unicode Consortium, 2012. ISBN 978-1-936213-02-3)
https://www.unicode.org/versions/Unicode6.1.0/
Version 6.0.0
The Unicode Consortium. The Unicode Standard, Version 6.0.0, (Mountain View, CA: The Unicode Consortium, 2011. ISBN 978-1-936213-01-6)
https://www.unicode.org/versions/Unicode6.0.0/
Version 5.2.0
The Unicode Consortium. The Unicode Standard, Version 5.2.0, (Mountain View, CA: The Unicode Consortium, 2009. ISBN 978-1-936213-00-9)
https://www.unicode.org/versions/Unicode5.2.0/
Version 5.1.0
The Unicode Consortium. The Unicode Standard, Version 5.1.0,
defined by: The Unicode Standard, Version 5.0 (Boston, MA,
Addison-Wesley, 2007. ISBN 0-321-48091-0), as amended by Unicode
5.1.0
https://www.unicode.org/versions/Unicode5.1.0/
Version 5.0.0
The Unicode Consortium. The Unicode Standard, Version 5.0.0,
defined by: The Unicode Standard, Version 5.0 (Boston, MA,
Addison-Wesley, 2007. ISBN 0-321-48091-0)
https://www.unicode.org/versions/Unicode5.0.0/
Version 4.0.1
The Unicode Consortium. The Unicode Standard, Version
4.0.1, defined by: The Unicode Standard, Version 4.0
(Boston, MA, Addison-Wesley, 2003. ISBN 0-321-18578-1),
as amended by Unicode 4.0.1
https://www.unicode.org/versions/Unicode4.0.1/
Version 4.0.0 with
Corrigendum
The Unicode Consortium. The Unicode Standard, Version 4.0.0,
defined by: The Unicode Standard, Version 4.0 (Boston, MA,
Addison-Wesley, 2003. ISBN 0-321-18578-1) and Corrigendum #5:
Normalization Idempotency
https://www.unicode.org/versions/corrigendum5.html
Versioned
Unicode Standard Annex #15,
"Unicode Normalization
Forms," edited by Ken Whistler, an integral part of The
Unicode Standard. Version 15.1.0. 2023-08-12. (https://www.unicode.org/reports/tr15/tr15-54.html)
Latest Version:
https://www.unicode.org/reports/tr15/
Versionless
Unicode Standard Annex #15, "Unicode Normalization
Forms," edited by Ken Whistler, an integral part of The Unicode
Standard.
(https://www.unicode.org/reports/tr15/)
Versioned
Unicode
Technical Standard #10,"Unicode Collation Algorithm,"
edited by Ken Whistler and Markus Scherer. Version 15.1.0. 2023-09-05. (https://www.unicode.org/reports/tr10/tr10-49.html)
Latest Version:
https://www.unicode.org/reports/tr10/
Versionless
Unicode
Technical Standard #10,"Unicode Collation Algorithm,"
edited by Ken Whistler and Markus Scherer. (https://www.unicode.org/reports/tr10/)
Versioned
Unicode Technical Report #25, "Unicode Support for Mathematics," by Barbara Beeton, Asmus Freytag and Murray Sargent III.
2017-05-30 (https://www.unicode.org/reports/tr25/tr25-15.pdf)
Latest Version: https://www.unicode.org/reports/tr25/
Versionless
Unicode Technical Report #25, "Unicode Support for Mathematics," by Barbara Beeton, Asmus Freytag and Murray Sargent III.
(https://www.unicode.org/reports/tr25/)